Place the flour in a large mixing bowl. If you’re using coloring powder add it to the flour and whisk well to combine.
Boil water and combine with salt. Add boiling hot water to the flour and combine with a pair of chopsticks or a wooden spoon.
Add sesame seed oil and continue to mix. When it becomes crumbled, use your hands to make a ball. Knead the dough in the bowl, until you pick up all of the dough on the side of the bowl.
Wrap with a cling wrap and rest for about 30 minutes.
Remove cling wrap and knead for a few minutes on a lightly floured bench top. When the dough surface becomes smooth, cover with cling wrap again and rest for further 30 minutes.
Divide the dough into two. Roll out flat on a lightly floured surface to about 1-2 mm with a rolling pin.
Cut out the dough into a round shape using a 11cm large cookie cutter.
Finely chop the cabbage, place it in a bowl and add 1 tsp salt to draw out the water. Set aside for 20 minutes.
Wrap the tofu with paper towels and place it on a plate. Weight it down with a heavy object for 15-30 minutes to drain the water.
After 20 minutes, squeeze the cabbage with a cloth or by hand.
Finely grind the tofu and the mushrooms and place them in a bowl.
Add soy sauce, sesame oil, salt and pepper, chopped spring onions and grated ginger.
Combine all the ingredients for the filling and fill the dumplings.
Place a heaping teaspoon of filling in the middle of each dumpling and fold in desired shape.
To cook the gyoza, pour just enough oil to cover a large skillet (about 1 tsp). Heat the oil over medium heat, add the gyoza.
When the bottoms get golden brown, add 1/4 cup of water, then immediately cover. Cooke for a couple of minutes o until all the water is evaporated.
You can freeze the uncooked gyoza. Place them on a baking sheet leaving some space between to keep them from sticking, and put in the freezer. Transfer frozen gyoza into a freezer bag and store in the freezer for up to a month. When you use frozen gyoza, do not defrost. Cook while frozen and steam for extra 1-2 minutes.